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A dimmer switch can be burned out if it is not functioning properly. There are several signs that indicate a burnt-out dimmer switch. Firstly, the switch may not turn on or off the lights at all. Secondly, the lights may flicker or dim inconsistently when the switch is adjusted. Thirdly, there may be a buzzing or crackling sound coming from the switch. Lastly, the switch may feel hot to the touch. If any of these signs are present, it is likely that the dimmer switch is burned out and needs to be replaced.
Dimmer switches have evolved since their invention in 1961 by Joel Spira. While they save energy and light bulbs, modern electronic dimmer switches are more susceptible to damage than their predecessors. Power surges or exceeding the rated wattage can cause damage to these solid-state devices. Fortunately, troubleshooting and replacing electronic dimmer switches is a straightforward process, even for beginners.
Bench Testing a Dimmer Switch
Step 1
To prevent shock hazards, place the dimmer switch on a non-conductive surface like a dry wooden workbench or rubber mat. Attach one end of the 110-volt test cord to one of the dimmer switch’s black wires.
Step 2
Turn on the AC voltage function switch on your digital multimeter (DMM). Set the range selector switch to 150 volts or higher. If you choose a lower voltage range, “O.L.” will appear on the LCD. Adjust the range selector to a higher voltage range.
Step 3
Connect one of the DMM’s test leads to the second black wire on the dimmer switch and the other test lead to the second 110-volt test cord lead. Ensure that the test leads are not touching each other or the metal strap of the dimmer switch. Plug the test cord into a 110-volt outlet.
Step 4
Operate the dimmer switch while observing the DMM’s LCD reading. The reading should vary linearly from zero to 120 volts and from 120 to zero volts if the switch is functioning properly. A continuous “zero” volts reading indicates a burned-out dimmer switch that needs replacement.
Testing an Installed Dimmer Switch
Step 1
Identify and turn off the circuit breaker that protects the branch circuit you will be working on.
Step 2
Detach the two screws that secure the cover plate at the dimmer switch. Remove the two screws that hold the dimmer switch in the device box and pull the switch from the box.
Step 3
Disconnect the nuts connecting the black wires on the dimmer switch to the black circuit wires. Link the two sets of black wires with the alligator-clip-equipped jumper wire. Ensure that the alligator clips do not touch the bare ground wire or the metal device box.
Step 4
Turn on the circuit breaker for the branch circuit at the switch box. If the light comes on, the dimmer switch is burned out and requires replacement.
Step 5
Before installing a new dimmer switch, turn off the circuit breaker again.